Attributes / relations provided by
♦ ¹del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona.
♦ ²Golden Eagles on the Swedish mountain tundra – diet and breeding success in relation to prey fluctuations, Jesper Nyström, Johan Ekenstedt, Anders Angerbjörn, Linda Thulin, Peter Hellström & Love Dalén, Ornis Fennica 83:145–152. 2006
♦ ³SUMMER DIET OF TWO SYMPATRIC SPECIES OF RAPTORS UPLAND BUZZARD (BUTEO HEMILASIUS) AND EURASIAN EAGLE OWL (BUBO BUBO) IN ALPINE MEADOW: PROBLEM OF COEXISTENCE, Qinghu CUI, Jianping SU, Zhigang JIANG, POLISH JOURNAL OF ECOLOGY, Vol 56, 1 pp. 173–179 (2008)
♦ ⁴The plateau pika (Ochotona curzoniae) is a keystone species for biodiversity on the Tibetan plateau, Andrew T. Smith and J. Marc Foggin, Animal Conservation (1999) 2, 235–240